Developmental Psychology
PIAGET (…and his critics)
1
Philosophical Background
Study of 'epistemology' dates to ancient Greek philosophers.
Focus on question "how do we come to know the world?" or
"where does knowledge come from?".
Cognitive Psychology is the modern study of the processes and
structures underlying knowledge
(i.e. thinking and remembering).
1.1
Where does Knowledge come from?
Three main positions:
1) Empiricism
- "blank slate" - Aristotle
- mental processes are seen as qualitatively similar in the child
and the adult human.
- child has had less experience of the world and therefore has
less knowledge
e.g. Behaviourism.
2) Rationalism
- "innate ideas" - Plato
- we are born with knowledge structures which subsequently
'unfold' or are discovered through the process of thinking.
- more recently, emphasis on maturation and self-contained
knowledge 'modules' which come 'on-line' at different stages
in development.
3) Constructivism / Interactionism
- Kant's synthesis of empiricist and rationalist ideas.
- born with very basic mental structure which imposes some
regularity on sensory information.
e.g. Piagetian theory.
Important to note that these distinctions persist in theories of
cognitive development to this day.
2
Key Points of Piaget's Theory
Piaget strongly influenced by Kant's constructivist theory of
knowledge. Formulated theory as alternative to and rejection of
behaviourist (empiricist) theories of development, which
account for development in terms of learning based on
associations between stimuli and responses.
In contrast, Piaget claimed that knowledge cannot simply
emerge from sensory experience; some initial structure is
necessary to make sense of the world.
Combined the biological notion of adaptation with Kant's
constructivism to produce a theory of the development of
adaptive knowledge which he called "genetic epistemology"
(the study of the growth of knowledge).
According to Piaget, children are born with a very basic mental
structure (genetically inherited and evolved) on which all
subsequent learning and knowledge is based.
Rather than seeing development as a quantitative increase
(e.g. behaviourists see development as an increase in
associations formed on the basis of an unchanging set of
processes), Piaget saw cognitive development as involving
qualitative change: the very foundations of thought change
and become more sophisticated as the child's intellect
develops.
Simon Ungar 2004
2.1
Logic and Rationality
- assumed that human intelligence is reducible to the laws of
formal logic. Logic and the methods of physics are the rational
basis for any objective, true knowledge of the world.
- Rational thought is seen as the 'goal' of cognitive
development.
- child acquires knowledge of the world by 'replicating the
discoveries of physics' (and of psychology).
- at any point in development, the level of the child's thinking
can be assessed in relation to the laws of formal logic.
2.2
Action
- physical activity seen as crucial in initial stages of cognitive
development.
• all early knowledge about the world comes from actions
upon objects in the child's environment.
• the function of reflexes is to bring the child into active
contact with objects and surfaces.
- ultimately, Piaget sees all thinking as a kind of action; at the
more advanced stages, action is thought about rather than
necessarily carried out.
2.3
Schemas
- a specific set of actions (physical or mental) applied to a
particular situation.
- schemas can be applied to other situations (as when we
assimilate new information to a particular scheme) in a
process of generalization.
- schemas can be combined to form more sophisticated
sequences of actions.
2.4
Stages
- thinking (intelligence) develops through an invariant sequence
of stages.
- at each stage, a new kind of thinking (i.e. a new level of logic)
replaces a more immature one.
- each stage can be characterised by the type of logic to which
the child’s thinking conforms.
- idea of an invariant sequence of development is central to this
model, the actual ages when children achieve different levels
of understanding is not.
2.5
Domain Independence
- Piaget's theory was intended to cover all areas (domains) of
mental life (perception, language, morality, number etc.).
- used the word 'intelligence' to describe this generalized
quality of thought.
- contrasts with recent nativist views (e.g. Chomsky) and with
Karmiloff-Smith's theory.
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What is the ‘Starting State’?
Piaget specified the minimal initial cognitive structure that the
child possesses at birth as being:
- a set of perceptual capacities
- a set of reflexes
- three generalized adaptive processes:
1) Assimilation
- bringing new information into an existing body of knowledge
by "filtering or modifying" the input.
(e.g. incorporating the concept 'dog' into the higher level
concept of 'animals').
s.ungar@surrey.ac.uk
2) Accommodation
- altering the knowledge structure to allow assimilation of new
information which is inconsistent with current knowledge.
(e.g. extending an existing concept to allow for a new,
inconsistent example).
3) Equilibration:
- Piaget believed that all human thought seeks order and is
uncomfortable with contradictions and inconsistencies in
knowledge structures. In other words, we seek 'equilibrium' in
our cognitive structures.
- there is a conflict between our drive to acquire knowledge
about the world (via assimilation) and a resistance to altering
our structures of knowledge (via accommodation).
- equilibration is the process through which this conflict is
settled.
Note that behaviourist theories also acknowledge the role of
perception and reflexes in development. The key difference at
this initial stage is in the three adaptive processes
4
Piaget's 'Clinical' Method
Developed method of investigating cognitive development
known as the 'clinical method'.
Children presented individually with a range of tasks using a
variety of materials designed to probe the level of logic
underlying their thought (examples below).
Piaget just as interested in reasons (older) children gave for
their answers as in the answer itself because:
- did not count an answer as correct unless child showed
evidence of correct reasoning (i.e. excluded answers where
child said "I just guessed")
- was equally interested in reasons given for wrong answers
5
The Stages of Development
According to Piaget, there are four identifiable stages in the
development of cognition:
5.1
Sensorimotor Stage
Birth to approx 2 years.
Period of rapid cognitive growth.
On basis of set of reflex movements, a set of perceptual
systems and three adaptive processes, infant quickly begins to
build up direct knowledge of world around, by relating actions to
results of those actions
Through assimilation and accommodation, actions become
progressively adapted to the world (e.g. grasping schema).
Circular Reactions:
Before 1 month, behaviour just reflex actions.
From 1 to 4 months
- primary circular reactions
- begins to notice when a reflex action brings about an
interesting (stimulating) result and attempts to repeat it (e.g.
repeatedly opening and closing hand, sucking thumb)
- intentional actions largely centred on own body and not yet
oriented to the environment.
- begins to adapt her actions towards fulfillment of needs (e.g.
opening mouth differently for teat and spoon).
NB: a circular reaction that can be repeated is a very simple
kind of internalised action and is therefore the earliest form of
schema.
Between 4 and 8 months
- secondary circular reactions
- also involve repetition of actions that have been encountered
through trial and error, but tend to be oriented towards actions
in the environment (e.g banging, reaching for and grasping
objects).
Simon Ungar 2004
From 8 to 12 months
- can coordinate two or more circular reactions together into a
more adaptive action pattern
- allows them to use existing action schemas together to solve
novel problems (e.g. retrieve a hidden object by first pushing
away a cover and then grasping the object).
- child is combining simple schemas into more complex,
articulated and more adaptive schemas.
Between 12 and 18 months
- tertiary circular reactions
- acquire new behaviours through active experimentation and
exploration in the world
- still use trial and error, but in more systematic way
18 months
- start of mental representation
- child can solve problems by manipulating internalised
representations of objects (i.e. instead of trial and error, child
can think through a problem)
Egocentrism:
Infancy characterised by extreme egocentrism:
- no understanding of world other than own, current point of
view
- main development during this stage is understanding that
objects exist and events occur in the world independently of
one's own actions ('object concept', or 'object permanence')
Object Permanence:
Typical test for understanding object permanence is a 'Search
Task': an object is hidden and the child then tries to find it.
'A-B' search task reveals progressive acquisition of object
concept during sensorimotor stage.
- two possible hiding places presented to child (e.g. two
handkerchiefs on a tabletop).
- object hidden under first hiding place (A) then moved to
second hiding place (B) (secretly or in view of child).
- developmental sequence of acquisition of object concept
revealed by child's responses to task:
Substage III: 4 - 8 months
Child will not search for a hidden object at all, even when she
sees it places under A. Eventually attempts to recover a
partially concealed object.
Substage IV: 8 - 12 months
When object is hidden under A, will attempt to retrieve it.
However if after a few of these trials object is first hidden under
A and then moved to B (in the child's view), will persist in
looking under A. ('A-not B' error or the 'Stage IV' error).
For Piaget, error is clear evidence of egocentric understanding
of the situation: child learns a response based on actions of first
uncovering and then grasping the object, but cannot generalize
action sequence to new situation, even though the situations
seem very similar to us.
Substage V: 12 - 18 months
Child has now mastered the basic A-B task, and reliably
searches in correct location even after a sequence of visible
displacements of hidden object. Significant because can now
represent existence and position of an invisible object. Earliest
instance of fully internalised thought; detached from visible and
tangible world.
But, only the case for objects they have seen being hidden. In a
variant of the A-B task, Piaget first placed the object in a
container, then moved object and container under a hiding
place. Object dropped out of container under hiding place and
container removed. Children search in container but do not go
on to look under hiding place. Can represent position of a
hidden object, but cannot track sequence of movements that
would lead them back to true hiding place.
2
Substage VI: 18 - 24 months
Child experiments with objects rather than just reproduce
familiar routines on particular objects. In the modified A-B task,
on finding that object is not in container, will experiment with
other possible locations and eventually find object.
5.2
Preoperational
By 2 years, children have made some progress towards
detaching their thought from physical world. However have not
yet developed logical (or 'operational') thought characteristic of
later stages. Thinking is still intuitive (based on subjective
judgements about situations) and egocentric (centred on the
child's own view of the world).
Conservation:
Intuitive and alogical aspects of pre-operational thought
revealed most clearly in tasks on 'conservation'. In physics,
notion of conservation is that as one aspect of a situation
changes, another stays the same (e.g. conservation of matter).
Conservation tasks present children with very simple physics
experiments to see if they understand this important logical
principle. Some examples of conservation experiments are:
Number: Two identical rows of identical counters presented to
child. Child asked whether both rows have same number.
Preoperational child can answer this correctly. Experimenter
spreads one row of counters out or pushes them together. Child
asked initial question again.
The child now says that the sausage has more clay than the
ball ("that one's bigger now").
So, what do these tasks tell us about the limitations of
preoperational thought in general?
Piaget drew a number of related conclusions:
1) Understanding of these situations is 'perception bound'.
Child is drawn by changes in the appearance of the
materials to conclude that a change has occurred.
2) Thinking is 'centred' on one aspect of the situation. Child
notices change in level of water or in length of clay without
noticing that other aspects of the situation have changed
simultaneously.
3) Thinking is focused on states rather than on
transformations. Child fails to track what has happened to
the materials and simply makes an intuitive judgement
based on how they appear 'now'.
4) Thinking is 'irreversible' in that the child cannot appreciate
that a reverse transformation would return the material to it's
original state. Reversibility is a crucial aspect of the logical
(operational) thought of later stages.
Class Inclusion:
Another indication of the lack of logical thought is the
preoperational child's inability to think hierarchically; to think
simultaneously about subordinate and super-ordinate
categories. E.g. child shown a set of counters four of which are
red and two of which are blue.
Young preoperational children say that the number of counters
in the two rows is now different (e.g. "there are more because
that line is longer").
Liquid: Child shown two identical beakers with the same
amount of liquid in each. The liquid from one beaker is poured
into a wider (or narrower) beaker.
Child asked: "Are there more red counters or more counters?".
Preoperational child answers that there are more red counters
(e.g. ...because only tow are white").
Child centres on most salient perceptual characteristic of
situation, & fails to consider hierarchical aspect of question (i.e.
total number of counters versus relative number of different
coloured counters).
Perspective:
Due to preoperational egocentrism, child can only appreciate
one perspective on a situation: her own. Piaget devised 'Three
Mountains' task to test children's understanding of perspective.
Child now says that there is less (or more) liquid in the second
beaker (e.g. "it looks lower").
Mass: Child is shown two identical balls of clay. One of the balls
is rolled into a sausage shape.
Child views a model of three mountains from one side, and is
asked to determine what another person sitting on other side of
model can see by choosing from four pictures of different sides
of model. Preoperational child chooses picture showing own
view of model.
Simon Ungar 2004
3
5.3
Concrete Operational
A major turning point in the child's cognitive development,
because marks beginning of logical/operational thought.
Operational thought is:
- relatively free from perceptual world
- relatively decentred
- conforms to physical laws such as reversibility and transitivity
(if A > B and B > C then A > C).
But operational thought only effective here if child asked to
reason about materials that are physically present. Will tend to
make mistakes or be overwhelmed when asked to reason
about abstract or hypothetical problems.
6.3
5.4
Light, Buckingham & Robbins (1979)
- children shown two identical beakers with same amount of
food in each.
- experimenter then points out that one of the beakers is
chipped, and suggests putting the contents in a third, different
shaped container for the sake of safety.
→ more children correctly say that there is still the same
amount of food.
Formal Operational
In contrast, formal operational thought is entirely freed from
physical and perceptual constraints. It becomes possible to
reason abstractly and hypothetically about the world. This stage
sees emergence of scientific thinking, formulating abstract
theories and hypotheses when faced with a problem.
6
Methodological Criticisms
Since early 1970s, an increasing amount of evidence has
suggested that P's methodology may have under-estimated
many of the child's abilities.
6.1
General
clinical method criticised:
- carried out his studies with a handful of participants – in the
early studies he generally used his own children
- no set procedure and no statistical analysis
- cross-sectional so can’t draw strong conclusions about
process of development from stage to stage
BUT: bear in mind that Piaget considered the method
appropriate for his aims:
- method requires flexibility, to allow the researcher to explore
the basis of each individual child’s reasoning
- consistent with structuralist theory of the time and with the
aims of genetic epistemology
(see Boden, 1996, for more on this).
6.2
Sensorimotor
A problem with Piaget's sensorimotor tasks is that require an
active response from infant (e.g. removing cloth and grasping
object). Child may be limited by other factors (e.g. immature
motor skills) rather than lack of understanding of situation.
Preoperational
It has been suggested that Piaget's tasks at this stage may
have underestimated the child's abilities due to a number of
factors including:
- complicated language.
- unfamiliar materials.
- lack of context.
- children misinterpreting experimenter's intention.
More recent studies have attempted to ask questions more
clearly and to present situations to which children can relate
more easily.
Suggests that context of task may be important for children's
understanding of the situation. As far as children are
concerned, adults rarely do something without a reason (e.g.
they wouldn't pour liquid from one place to another unless they
wanted to change something; they wouldn't ask a question
unless something had in fact changed).
By providing a clear reason for making the change (e.g. the
chipped beaker) this allows some children to concentrate more
on the materials.
McGarrigle (see Donaldson 1978)
- presented children with Piagetian conservation tasks.
- instead of experimenter, a character called 'Naughty Teddy'
performs transformation (means that the act of transforming
the situation is divorced from the experimenter's second
question).
→ 70% of 4 - 6 year olds passed this version of the task.
Suggests that differences in 'meaning' children ascribe to
situation might cause them to pass or fail task.
McGarrigle (see Donaldson 1978)
- suggested that class inclusion task is hard, because question
doesn't make super-ordinate category salient.
- presented children with a modified version of the task making
super-ordinate category more salient.
Recent research has used a habituation technique to probe
child's understanding of object permanence.
Baillargeon et al. (1985)
- habituated child to screen that moved back and forth like a
drawbridge through a 180° arc.
- a yellow box placed behind the screen.
- child then shown one of two test situations:
1) Possible Event: the screen is rotated up from a flat
position until it rests against the box where it stops before
returning to the original position.
2) Impossible Event: the screen rotated up from flat position
and appeared to move through the box before returning to
original position.
- one group of children asked typical question: "Are there more
black cows or more cows?".
- another group of children told that ALL the cows were
sleeping, and then asked: "Are there more black cows or
more sleeping cows?"
(note that this is still a class inclusion question).
→ infants as young as 3.5 months looked longer at the
impossible event.
→ only 25% of the first group answered correctly.
→ 50% of the second group answered correctly.
Suggests infants were surprised at this event and expected
screen to come to rest against box even though it was out of
sight.
Although performance not perfect with modified task, results
show that at least a proportion failed the original task because
of the way it was presented.
Simon Ungar 2004
4
Hughes (see Donaldson 1978)
- devised a version of the Piagetian perspective taking task
which would make 'human sense' to a child.
- children shown a board with two barriers.
- toy policemen placed at the end of each barrier.
- child asked to place a model boy in the layout where the
policeman can't see him.
7
Theoretical Criticisms
7.1
The Role of Culture in Development
Emphasises that the child's cognitive development can only be
properly understood in the context of their culture and
interactions with others.
See Vygotsky lectures.
7.2
Structure versus Process
Piaget's theory emphasises the structure of the child's
knowledge at each of the stages of cognitive development, and
does not elaborate much on the processes underlying
development. Information Processing theories of development
try to specify the processes involved in cognitive development
explicitly by applying models of memory.
See Information Procssing lecture.
7.3
Nativism - Modularity
Also formulated as a reaction against radical behaviourism, but
goes further than Piaget to suggest that a large proportion of
mental structure is innate.
Many preoperational children succeeded in placing model boy
in section 'd' suggesting that they could understand the
perspective of the two policemen.
Das Gupta & Bryant (1989)
- showed children sequences of pictures depicting simple,
familiar events in which an object was transformed in some
way.
- two types of event were shown:
1) an object goes from it's basic state to a changed state (e.g.
a cup became a wet cup).
2) an object goes from a changed state to it's basic state (e.g.
a wet cup becomes a dry cup).
- children asked to choose one item out of three that caused the
object to change (e.g. water, cloth, feather)
-> 3 year olds generally picked the same item (water) for both
transformations.
-> 4 year olds generally choose different and appropriate items
for each transformation.
Suggests that 4 year olds can understand a simple, familiar
transformation and follow it mentally in both directions
(reversibility).
6.4
Summary
Taken together, these methodological reassessments call into
question the reliability of Piaget's findings. It may be that some
of his tasks were easier and some harder, but for relatively
trivial reasons (e.g. the child misunderstands the experimenter's
intention).
All of the experiments with pre-operational children introduce
tasks that have "human sense", in that they use language,
materials, contexts and activities that are familiar to the child.
We say that these tasks are embedded in contrast to Piaget's
disembedded tasks.
A counter-criticism, however, would be that Piaget was
specifically interested in 'disembedded' thought, on other words
he was specifically testing the child's ability to decentre from
familiar contexts and to generalize their knowledge to new and
unfamiliar situations.
Simon Ungar 2004
Piaget saw early thought as undifferentiated and fused
together; cognitive development is a process of differentiation,
where thought becomes generalised and specialised. The
modular view is that the brain is already differentiated and
specialized at birth, consisting of modules that have evolved to
perform distinct cognitive tasks. Not all the modules are (fully)
functional at birth, some come into operation later as a result of
maturation of in response to certain kinds of structured input.
Three main figures associated with modularity:
Fodor (1979)
Whereas Piaget's response to the behaviourists might be: "You
can't get something from nothing", Fodor might say to Piaget:
"You can't get a more powerful way of thinking out of a less
powerful one".
Fodor's is a general and very radical critique of Piagetian
theory. According to Piaget, each successive stage of
development sees the child operating with a more powerful set
of logical operations than the previous stage. Fodor has
attempted to show that this would be impossible; a more
powerful logical system can't simply emerge from a less
powerful one, just through the process of learning and
experience.
BUT: fails to account for developmental processes - if modules
present at birth, how does cognition change?
Chomsky (1957) - Language Acquisition Device.
Focused on language development, but made waves for
Piaget, because Piagetian theory is supposed to account for all
areas of learning including language. Chomsky argued that a
general constructivist theory could not account for language
learning. Child is exposed to degenerate linguistic data,
therefore must be applying linguistic structure from 'inside'.
Proposed a 'Language Acquisition Device' (LAD) which is a
mental module specifically dedicated to detecting and analysing
linguistic information from the child's environment.
Gardner (1983) - Multiple Inteligences
Collected together data on performance on many different
types of task. Suggested that the brain is divided into several
specialised systems which deal with different kinds of
information. Proposed seven distinct 'intelligences' that we
posses:
5
•
•
•
•
•
•
•
Linguistic
Logical-Mathematical
Spatial
Musical
Bodily-Kinaesthetic
Interpersonal
Intrapersonal
Gardner proposes a set of eight criteria which are used to
determine if a particular ability constitutes a distinct intelligence:
• Potential isolation by brain damage
• The existence of idiots savants, prodigies etc.
• Identifiable set of specific operations
• Distinctive developmental history
• Distinctive evolutionary history
• Support from experimental psychology
• Support from psychometric findings
• Encoding as a distinct symbol system
7.4
Modularization
Karmiloff-Smith (1992) started off within a Piagetian framework,
but recognized the problems raised by evidence from
psychopathology that very specific abilities can be affected,
while the rest of cognition remains unaffected (e.g. savant
syndrome, Williams Syndrome).
However, not convinced by strict Fodorian position, because
doesn't account for developmental change and implies a rigid
structure which is not consistent with cognitive flexibility.
Proposed a synthesis between constructivist and nativist
positions. Cognition begins general, but specific abilities
become differentiated, modularised and localised in the brain.
8
References
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Children's Development. Oxford: Blackwell.
* Bremner, J.G. (1994). Infancy. Oxford: Blackwell.
* Donaldson, M. (1978). Children's Minds. Glasgow: Fontana.
Baillargeon, R. (1987). Object permanence in 3.5- and 4.5month-old infants. Developmental Psychology, 23, 655-664.
Boden, M. (1994). Piaget (2
nd
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Das Gupta, P. & Bryant, P.E. (1989) Young children's causal
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Gardner, H. (1983). Frames of Mind: the Theory of Multiple
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Gruber, H.E. & Vonèche, J. (eds) (1977) The Essential Piaget.
London; Routledge.
Karmiloff-Smith, A. (1994). Beyond Modularity: A
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Siegler, R. & Wagner Alibali, M. (2005). Children's Thinking [4
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th
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Simon Ungar 2004
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